Frustrated with adidas online services

I'm so frustrated and disappointed with the service I've received from Adidas. I made a purchase twice online and both times it has been unpleasant.

On my first purchase i bought slides, and when i received them the size was too small. I then made return request on their website and I've waiting now almost 3 weeks for the slides to be picked up. When i spoke to one of customer care consultants she told me that i was supposed to buy 2 sizes bigger than my normal size because the cuts are too small on the slides, but isn't that information they supposed to share on the website before you purchase. Again the courier service they currently use is ridiculous. Courier operators between 8-5 but both my packages were delivered at 8pm and with no communication in advance.

With my second purchase i bought sneaker and i specifically called the customer care for sizes before making the purchase and she assured that i wont have the same size issue i had with slides, last night my shoes were delivered and again the size is too small, after making an effort and called adidas customer care regarding sizes. I'm so annoyed, now I'm stuck with items i cannot use.